In the early morning darkness, Devendran P. walks up a hill to a solar observatory in India’s southern hill town of Kodaikanal, trudging the same path his father and grandfather walked in a century-old family tradition of studying the sun.

Once inside, he pulls a rope to open shutters in the dome and positions a six-inch telescope used since 1899 to photograph the sun and preserve a daily record of its activity.

“The sun, like stars, has a lifetime of 10 billion years,” Devendran told Reuters during a recent visit to the observatory in India’s southern state of Tamil Nadu. “If you want to know about any small changes, you need to have a large amount of data.”

Observation records are seen inside the library at the Kodaikanal Solar Observatory, India, Feb. 3, 2017.

Daily activity of the sun

The observatory run by the Indian Institute of Astrophysics has a key role in providing a continuous stream of data on the sun and its influence on Earth and surrounding space, said R. Ramesh, a professor at the institute.

“Some of the discoveries made, based on data obtained in the Kodaikanal observatory, are so fundamental to solar physics that they vastly improved techniques used at observatories even today,” Ramesh said.

The Evershed effect of gas motion in sunspots, discovered in 1909 by the then director of the observatory, John Evershed, is one such example, he added.

Volumes of observation records are seen inside the library at the Kodaikanal Solar Observatory, India, Feb. 3, 2017.

In the observatory library, shelves stretch to the ceiling, packed with volumes of handwritten records and thousands of film plates of the sun. Authorities have launched a project to digitize and preserve the data collected over the past century.

Devendran’s grandfather, Parthasarathy, joined the observatory in 1900, a year after it relocated from Madras, the state capital, to Kodaikanal, situated more than 2,000 meters (6,562 feet) above sea level, offering ideal weather to study the sun.

Like his father and grandfather, Devendran has no formal education in astronomy. His interest was piqued during a visit to the observatory when he was a child.

Devendran (right) and his father Paramasivan, pose for a photograph inside an observation dome at the Kodaikanal Solar Observatory, India, Feb. 6, 2017.

He became a fulltime sunwatcher in 1986 and says the six-inch (15-cm) telescope has never failed his family.

“It has never required any major overhaul, or change of parts, because we all take care of it,” he said.

More than three decades of observation has made him feel close to the sun, despite its distance of more than 149 million kms (93 million miles) from Earth. It’s a feeling enhanced by the devout family’s worship of the Hindu sun god Surya, he said.